(1) Summary of the Invention
The present invention relates to a method and apparatus for detecting defects, surface or internal, in a spherical object. In particular the present invention relates to a method and apparatus wherein the spherical object is simultaneously rotated on its polar and equatorial axis adjacent a detector means which senses the defects. The ball is in contact with drive roller means which cause rotation in the vertical axis to thereby produce precise precession of the ball and scanning in one-half horizontal revolution of the ball.
(2) Prior Art
Various means have been used to detect defects in spherical objects, particularly ball bearings. U.S. Pat. No. 2,051,695 to Glacy (1936) describes a device for rotating spherical objects on a horizontal and vertical axis for testing. The problem is that the device is adapted to test only one size of spherical object. The testing of the ball is random in that the surface is not tested in a precise precession of the ball. Other less closely related patents describing the testing of spherical objects are U.S. Pat. Nos. 2,701,055 to Strom (1955); 2,778,497 to Bickley (1957); 2,845,177 to Perkins et al (1958); 2,982,402 to Dion (1961); 3,034,396 to Wilcox (1962) and 4,580,097 to Bartlett (1986). Soviet Union Patent Nos. 693241 (1979) and 868546 (1981) generally describe using eddy current testing of balls. U.S. Pat. No. 4,551,677 to Bankston (1985) also shows eddy current detectors.